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            <h2 class="title" style="clear: both"><a id="dbset_errcall"></a>DB-&gt;set_errcall()</h2>
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      <pre class="programlisting">#include &lt;db.h&gt;

void
DB-&gt;set_errcall(DB *, void (*db_errcall_fcn)
    (const DB_ENV *dbenv, const char *errpfx, const char *msg));  </pre>
      <p>
        When an error occurs in the Berkeley DB library, 
        <span>
                a Berkeley DB error
        </span>
         
         or an error return value is returned by the interface.  In some cases,
         however, the <span class="bold"><strong>errno</strong></span> value may be
         insufficient to completely describe the cause of the error, especially
         during initial application debugging.
    </p>
      <p>
         The <a class="xref" href="envset_errcall.html" title="DB_ENV-&gt;set_errcall()">DB_ENV-&gt;set_errcall()</a>  and
         <code class="methodname">DB-&gt;set_errcall()</code> methods are used to enhance the mechanism for
         reporting error messages to the application. In some cases, when an
         error occurs, Berkeley DB will call <span class="bold"><strong>db_errcall_fcn()</strong></span> 
         with additional error information.  It is up to the 
         <span class="bold"><strong>db_errcall_fcn()</strong></span> function to display the error
         message in an appropriate manner.
    </p>
      <p>
         Setting <span class="bold"><strong>db_errcall_fcn</strong></span> to NULL
         unconfigures the callback interface.
    </p>
      <p>
         Alternatively, you can use the
            
         
         <a class="xref" href="dbset_errfile.html" title="DB-&gt;set_errfile()">DB-&gt;set_errfile()</a>  or
         <a class="xref" href="envset_errfile.html" title="DB_ENV-&gt;set_errfile()">DB-&gt;set_errfile()</a> 
         methods to display the additional information via a C library <code class="literal">FILE *</code>.
         
    </p>
      <p>
         This error-logging enhancement does not slow performance or
         significantly increase application size, and may be run during normal
         operation as well as during application debugging.
    </p>
      <p>
         For <a class="link" href="db.html" title="Chapter 2.  The DB Handle">DB</a> handles opened
         inside of Berkeley DB environments, calling the 
         <code class="methodname">DB-&gt;set_errcall()</code>
         method affects the entire environment and is equivalent to calling the
         <a class="xref" href="envset_errcall.html" title="DB_ENV-&gt;set_errcall()">DB_ENV-&gt;set_errcall()</a> 
         method.
    </p>
      <p>
        When used on a database that was <span class="emphasis"><em>not</em></span> opened in
        an environment, the <code class="methodname">DB-&gt;set_errcall()</code>
        method configures operations performed using the specified 
        <a class="link" href="db.html" title="Chapter 2.  The DB Handle">DB</a> handle, not all operations
        performed on the underlying database.
    </p>
      <p>
         The <code class="methodname">DB-&gt;set_errcall()</code> method may be called at any time during the
         life of the application.
    </p>
      <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
        <h3 class="title">Note</h3>
        <p>
            Berkeley DB is not re-entrant. Callback functions should not attempt to make library
            calls (for example, to release locks or close open handles). Re-entering Berkeley DB is
            not guaranteed to work correctly, and the results are undefined.
        </p>
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      <div class="sect2" lang="en" xml:lang="en">
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              <h3 class="title"><a id="idp50239168"></a>Parameters</h3>
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        <div class="sect3" lang="en" xml:lang="en">
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                <h4 class="title"><a id="idp50239360"></a>db_errcall_fcn</h4>
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          <p>
                The <span class="bold"><strong>db_errcall_fcn</strong></span> parameter is the
                application-specified error reporting function.  The function takes
                three parameters:
            </p>
          <div class="itemizedlist">
            <ul type="disc">
              <li>
                <p>
                        <code class="literal">dbenv</code>
                    </p>
                <p>
                         The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing
                         database environment.
                    </p>
              </li>
              <li>
                <p>
                        <code class="literal">errpfx</code>
                    </p>
                <p>
                         The <span class="bold"><strong>errpfx</strong></span> parameter is the prefix
                         string (as previously set by 
                         <a class="xref" href="dbset_errpfx.html" title="DB-&gt;set_errpfx()">DB-&gt;set_errpfx()</a>  or 
                         <a class="xref" href="envset_errpfx.html" title="DB_ENV-&gt;set_errpfx()">DB_ENV-&gt;set_errpfx()</a> ).
                    </p>
              </li>
              <li>
                <p>
                        <code class="literal">msg</code>
                    </p>
                <p>
                         The <span class="bold"><strong>msg</strong></span> parameter is the error
                         message string.
                    </p>
              </li>
            </ul>
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        </div>
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      <div class="sect2" lang="en" xml:lang="en">
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            <div>
              <h3 class="title"><a id="idp50245976"></a>Class</h3>
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        <p>
                <a class="link" href="db.html" title="Chapter 2.  The DB Handle">DB</a>  
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      <div class="sect2" lang="en" xml:lang="en">
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              <h3 class="title"><a id="idp50240072"></a>See Also</h3>
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        <p>
                     <a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a> 
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